Solution to Denizen of the Deep

Each image clues a phrase of the form "X of the Y"

Freedom of the Press
King of the Hill
Planet of the Apes
Revenge of the Nerds
Sign of the Times
Out of the Ordinary
Run of the Mill

The first letters of the second words read: PHANTOM. Using the second word from "Phantom of the Opera", the answer to the puzzle is OPERA.